1. Filed of the Invention
This invention relates to the field of submersible motor and pump protection.
2. Description of the Prior Art
In recent years, many devices have been utilized to provide a signal upon a bearing failure, and in most devices the signal does not occur until the bearing has completely failed. Some bearing failure indicators are adaptable to pumps having vertical drive shafts. Some bearing failure indicators are used with a motor having a horizontal shaft and are concerned with movement in a radial direction of the shaft as opposed to axial movement of a shaft. Some bearing failure indicators are concerned with an alarm when the output flow of the pump fails. However, there are many special problems involved with submersible pumps and motors and therefore limit switches used for other installations are not applicable to the submersible motor and pump.
Applicant was aware of the following U.S. Patents at the time of filing this application:
U.s. pat. No. 2,577,559 -- Armstrong PA0 U.s. pat. No. 3,050,003 -- Edwards PA0 U.s. pat. No. 3,373,300 -- Sullivan PA0 U.s. pat. No. 3,508,241 -- Potter PA0 U.s. pat. No. 3,853,087 -- Aldag